This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Pituitary function is rarely considered in the care of pediatric patients with traumatic brain injury (TBI). TBI poses signnificant risk to pituitary function given the gland's location within the sella tucica and a vulnerable vascular supply. The mechanism by which damage may be sustained may result from direct mechanical trauma, or low cerebral blood flow states associated with shock or intracranial hypertension. Numerous case reports have noted abnormalities in the hypothalamic-pituitary axis (HPA) in children after craniocerebral injury whether it is acquired perinatally or from accidental or non-accidental trauma. There have been no prospective studies regarding the occurrence of acute post-traumatic hormonal deficits and associated risk factors. This is a pilot study examining the occurrence of unrecognized secondary or tertiary acute adrenal insufficiency (AAI) in children who are subjected to moderate and/or severe TBI of any etiology. To account for the homronal stress response, the TBI children will be compared to a control group of children with extra-cranial injuries. A secondary evaluation will be made between accidental and non-accidental head trauma patients. For severity of illness comparison PRISM (Pediatric Risk of Mortality) scores are calculated for all children entered into the study. A scoring system will be employed to quantify risk factors, and an attempt to detrmine a relationship between the derived score and presence of AAI will be undertaken.